Food allergies on the rise, reasons elusive

Parents are reporting more skin and food allergies in their children, a US government survey has found.

Experts are not sure what is behind the increase.

Could it be that children are growing up in households so clean that it leaves them more sensitive to things that can trigger allergies?

Or are parents paying closer attention to rashes and reactions, and more likely to call it an allergy?

“We don’t really have the answer,” says senior report author Dr Lara Akinbami, of the US Centres for Disease Control and Prevention.

The survey suggests that about one in 20 US children have food allergies. That is a 50% increase from the late 1990s. For eczema and other skin allergies, it is one in eight children, an increase of 69%. It found no rise, however, in hay fever or other respiratory allergies.

Food allergies tend to be most feared. Severe cases may cause anaphylactic shock or even death from eating, say, a peanut. But many food allergies are milder and something children grow out of.

It has been difficult getting exact numbers for children’s allergies and the new report is not precise. It uses annual surveys of thousands of adults interviewed in person.

The report compares answers from 1997-99 to those from 2009-11. It found food and respiratory allergies are more common in higher-income families than the poor,

One of the more popular theories to explain the growth of allergies is “the hygiene hypothesis”, which says that exposure to germs and parasites in early childhood somehow prevents the body from developing certain allergies.

The hypothesis argues that there is a downside to America’s culture of disinfection and overuse of antibiotics.

The argument has been bolstered by a range of laboratory and observational studies, including some that have found lower rates of eczema and food allergies in foreign-born children in the US.

Dairy leads in NZ
New Zealand research by the CensusAtSchool project, which surveyed 10- to 18-year-olds, found dairy was the top allergy, followed by peanuts and eggs.

Early results from the first 2800 respondents showed 8.5% of students had some kind of food allergy, with 3.5% stating dairy, 2.5% peanuts and 2% eggs.

Wheat, tree nuts, shellfish, fish and soy all came next, with less than 1.9% of students suffering from allergies to these food substances.